Process for breaking petroleum emulsions



Patented Nov. 23, 1948 UNITED rnocnss FOR BREAKING PETROLEUM n ULsIoNs Melvin De Groote, University City, and Owen H. Pettingill, Kirkwoo'd, Mo., assignors to Petrolite Corporation, Ltd., Wilmington, DeL, a corporation of Delaware No Drawing. Application March 12, 1947, Serial No. 734,212

9 Claims. 1

an economical and rapid process for separating emulsions which have been prepared under controlled conditions from mineral oil, such as crude oil and relatively soft waters or weak brines. Controlled emulsification and subsequent demulsification, under the conditionsjust mentioned, are of significant value in removing impurities, particularly inorganic salts from pipeline oil.

Demulsification, as contemplated in the present application, includes the preventive step of commingling the demulsifier with the aqueous component which would or might subsequently become either phase of the emulsion, in absence of such precautionary measure. Similarly, such demulsifier may be mixed with the hydrocarbon component.

Cashew nut shells can be solvent extracted to yield a liquid sometimes referred to as. cashew nutshell liquid), Such product isnot an article of commerce and, presumably,'wou1dbe better designated as untreated cashew nutshellliquid. Reference in commerce to cashew nutshell liquid invariably refers to the product obtained by distillation of the cashew nutshells in which pyrolysis is involved. Such pyrolysis, among other things, eliminates thecarboxyl radical of the untreated cashew nutshell liquid.

The herein described new chemical products, compounds, or compositions-of matter which are used as the demulsifying agent in our process consist of drastically oxidized (treated, i. e., pyrolyzed) cashew nutshell liquid and the oxyalkylated derivatives thereof. It is believed that treated cashew nutshell liquid consists principally of pentadecenylphenol (dihydroanacardol) and lesser amounts of pentadecadienylphenol (anacardol). The raw materials employed in the present invention are prepared from the phenolic compositions present in or derived from the oils extracted from the anacardium genus of theanacardiaceae family. Untreated cashew nutshell liquid is described as consisting of. about 2 of anacardic'acid C22H32O3 and about 10% of cardol, 0321-15204, with very small fractional percentages of ether materials. The generally accepted formula of anacardic acid is As previously stated, pyrolytic distillation causes conversion into phenols. As to further information regarding cashew nutshell liquid and its phenolic derivatives, see J. A. C. S.,v volume 68, No.2, p.345.

It is well known that when certain fatty acids and particularly their glycerides are subjected to drastic oxidation with a gaseous oxygenating medium such as air, certain complicated changes take place, which are obscure and not readily susceptible to complete explanation. Examples of oils subjected to oxidation and commonly marketed as blown oil, are particularl castor oil and also soyabean oil. 1

Thus, it is well known that oxidized oils can be obtained from castor oil, ricinoleic acid, and

various derivatives of ricinoleic acid, such as monoricinolein, diricinolein and polyricinoleic acids. They are produced by the common practice of blowing or oxidizing castor oil and similar fatty oils or acids, particularly non-drying, unsaturated fatty oils, by means of a gaseous medium, such asair, oxygen, ozone, or ozonized air. The gaseous medium, such as air, may be moist or dry and the oxidation may take place in the presence or absence of a catalyst. The catalyst may be of a metallic type, such as lead ricinoleate, cobalt ricinoleate, manganese ricinoleate, etc., or it may be of the organic type, which produces peroxide, such as alpha-pinene, linseed oil, etc. Oxidation may take place-at atmospheric pressure or superatmospheric pressure, i. e., pressures up to or including 200 pounds gauge pressure, and at any temperature slightly above the boiling point of water, for instance, (3., up to any temperature which does not produce undue decomposition by pyrolytic reaction.

The time of blowing may be fairly brief, for example, 8-10 hours; or it may be quite extensive, for instance, as long as 10-12-14 days, the

longer time periods being employed generally when the temperature is just slightly above the boiling point of water, and when oxidation is with air at atmospheric pressure.

One method of preparing drastically-oxidized castor oil is described in U. S. Patent No. 2,023,979, dated December 10, 1935, to Stehr. Also see U. S. Patent No. 2,183,487, dated December 12, 1939, to Colbeth.

Oddly enough, phenolic materials" are" frequently used as inhibitors to prevent deterioration by oxidation. A phenolic group seems to be an effective inhibitor of oxidation. Notwith-- standing this fact, we have found-that.thesame..- conventional procedure or procedures employed.

for the oxidation of castor oil or similar compounds is equally suitable for the bl'owingxor oxidation of treated cashew nutshell liquid, or" its two principal constituentsto w-it; pentad cenylp-henol or pentadecadienyl-phen-ol. In most instances, the period and conditi'onsrof oxidation are apt to be approximately the same as castor? oil. For instance, we have been able to drastically-oxidize treated cashew nutshell liquidin" approximately a weeks time, using a temperature "of "HO-120 C. l'fa catalyst'is-em-ployed", the

periodcan be shortened.- This is also true-if a higher temperature-is used or ahigherapressure employed. Our preference,- however; is 'to use mild conditions of oxidation which would, for example, require about aweek or ten days for the oxidation of castor oil. As stated, the period of oxidation canbe'shortened or speeded up in the same way that the -oxidation of castor oilucan. beshortenedor accelerated. As is previously. pointed out; cashew nutshell liquid of commerce and, in fact, the only one ordinarily obtainable, is that which has been'treated, i. e.;

pyrolyzed. For convenience of terminology and:

particularly in that theterminology herein employed con-forms to that of commerce,.subsequent reference. to cashew nutshell liquidmeans the productobtainedby, distillation involving pyrolysis and isthe treatedmaterial. specificity, however, the. word ftreat'ed has been included in theclaimsa Regardless of-the method employed, it is our preference to oxidize just short of the. point where. the :reactingmass. would .convert into insoluble or. rubbery materials. Thus, vwhile the initial-reactants arecomparativelythin and show aviscosity. of..that of ordinary, oils, the finished product shows a viscosity of that of .blowncastor oil .andalso perhaps an-incipient. tendency. twardsstringiness. toofar, the material may go toaninsoluble mass, or. may. simply. cause. lumps or. a, semirubbery state, which isnot particularly suitable,

and which, as amatter of .fact, tends. tohresist solutionin thecommon solvents, whicharesuitable. for resolving drasticallyeoxidized. cashew" nutshell liquid and .thelike. Briefly, inwanyoperation. involving the gaseous oxidation of cashew nutshell. liquid or pentadecenylphenol: or. penta,

decad-ienylphenol, all .that is required isthat the:

operation beconductedto the point justsho-rt of therubbery or insoluble stringy state. Needless indicated. oxidation of: castor "oi-l,v insofar that blown. castor oil :is J ordinarlyoffered i in": three. grades, to wit, light .blown, medium blown, and heavily blown.

An additionalin'dex :andr a :means for-measur ingethezdegrees of oxidation" along with increase inviscosity; etc;, is the fact: that as oxidation: takes place, there is adefinitesdevelopment of aniacid' number or "saponification number; There is For purpose of If .the reaction is conducted also a change in the iodine number and in the hydroxl number. The following table gives the values in respect to the unoxidized cashew nutshell liquid and a sample of drastically-oxidized cashew nutshell liquid. Note'thatoxidation increases acidity;

Blown Cashew Cashew Nlltsh? Nutshell Liquid Liquid Acid value 11.2 27.0 Sa'ponification value 11.6 27. 4 Hydrox-yl value 196. 0 177. 6 Iodine (Wijs) 202. 2 201. 0

may also changeto a deep amber on even black.

It-is well "known thatthe exact composition of'ordinary oxidized castor oil is not known. This has been a matter of comment from time to time, in the literature, including the patent literaturedealing with arts in which blown castor oil is contemplated. Obviously, even less is known in regard to the change which-takes place during the drastic oxidation. of cashew nutshell liquid and "its components.

has been previously pointed out, the same conventional procedure or processes employed for the oxidation of castor oil or similar compounds is equally" suitable for the blowing or oxidation of cashew nutshell liquid. This applies to'the ordinary product of commerce, or the product obtained by more careful distillation or re-distillation so as to give a product free from certain non-phenolic co-gen-ers. The values above given for blown cashew nutshell liquid, represent'a product which was blown for 168 hours at120" C. with ordinary air, carrying usual climatic moisture. No-catalyst was added. If desired," th'e'same degree of oxidation can be accomplished at C. if one increases the time to 220 h'ours.- The above product would represent medium oxidation; If desired, a lightly oxidized oil'could be obtained" by limiting the oxidation periodktoapproxlmately 90% of that'previously indicated, that'is, 90% of 168 hours at C. Similarly, a heavily oxidized'oil can be obtained by increasing: the time of oxidation approximately 5% to 10%, or in any othersuitable manner, such as increasing the temperature slightly, or using a catalyst. Certain oxidation catalysts have been .previously'mentioned in connection with'derivatives'of castor oil and these can' 'also be used-in connection with the blowing of cashew nutshell liquid. Hereafter, reference to these three types will be employed and they will be indicated as cashew nutshell liquid light blown, cashew nutshell liquid medium blown, and cashew nutshell liquid heavily blown. The latter product is characterized by incipient stringiness or sem-rubberiness, but is still susceptible to oxyalkylation', particularly oxethylation, so as to yield fawater soluble or water-emulsifiable product. The color-of the blown product was deep amber; or almost black.

Having obtained a drastically-oxidized cashew 'nutshelliliquid or drastically-oxidized pentadec'enylphenol; orv drastically-oxidized pentade-T cadienylphenol, such intermediate is treated with an oxyalkylating agent, preferably ethylene oxide, propylene oxide, butylene oxide, glycidol, methylglycidol, orthe like. I

It is well know that phenols and carboxy acids can be subjected to oxyalkylation so asto yield products which have enhanced hydrophile properties, and may be oxyalkylated, if desired, under appropriate conditions togive completely watersoluble products. As to patents which describe the oxyalkylation of car-boxy acids or phenols, see U. S. Patent No. 1,826,900, dated October 13, 1931, to Schrader; and British Patent No. 470,181, to Wilfred Wm. Groves.

Thus, the conventional oxyalkylating procedure is well known, and generally speaking, involves nothing more nor less than heating a fatty acid, for instance, oleic or stearic acid, or a phenol, such as any of the ordinary phenols, in thepresence of successive small amounts of an alkylene oxide, or the like, under comparatively low pressures and fairly low temperatures, and usually in the presenceofan alkaline catalyst, as, for example, sodium oleate, caustic soda, sodium carbonate, sodium methylate, etc. The temperaturesemployed are above 100 C. and below 200 C. The pressures employed are generally above 100 pounds gauge pressure, and below 300 pounds gauge pressure. Sometimes oxyalkylation is conducted in a continuous manner by the introduction of ethylene oxide in a gaseous state. More frequently and most conveniently, the oxide is introduced in liquid form in comparatively small amounts, for instance, 200 pounds of the material to be oxyethylated. such as drastically-oxidized cashew nutshell liquid and 30 pounds of ethylene oxide along with approximately a pound of sodium methylate. In such instances, where the drastically oxidized cashew nutshew liquid is prepared for oxyalkylation, and particularly oxyethylation, we prefer to add a small amount of alkali at the completion of the oxidation stage, so that it can be converted into a soap or phenolate, and thus serve as a catalyst. For instance, we prefer to add approximately of caustic soda or causticpotash to the drastically-oxidized cashew nutshell liquid and heat to 120 C. long enough to drive off the water used to dissolve the alkali or resulting from the neutralization reaction. The oxyethylation reaction is allowed to take place under pressure in the manner above described, until all the ethylene oxide or other alkylene oxide is absorbed. Another portion of ethylene oxide is added and the procedure repeated until the desired stage of hydrophile character is obtained. Initial hydrophile character is indicated by the fact that the product shows self emulsifiability in water. Complete or maximum hydrophile character is shown when the product will dissolve in water to give a clear solution, andinfact, will form a clear solution even in the presence of modest amounts of a water-insoluble solvent, such as to of xylene.

Theoretically, the alkylene oxide can combine with the phenolic hydroxyl radical with any carboxyl radical, and probably with hydroxyl radicals which have come into existence in the aliphatic chain, as a result of the oxidation reaction. Thus, as is illustrated by the example previously noted, onecan add the hydroxyl value to the carboxyl value and assume that this represents an approximate equivalent of the amount of alkylene oxide required in mono molar of the drastically-oxidized cashew nutshell liquid or its equivalent with one to five pounds of the oxyalkylating agent. Our preference is to use ethylene oxide, primarily due to its cost and its greater reactivity. More propylene oxide or butylene oxide would be required than ethylene oxide to give the same hydrophile effect and materials. Less glycide is required than propylene oxide, and less methylglycide than butylene oxide. We have found, however, that regardless of which alkylene oxide is employed, as soon as a stage isreached varying from initial self-emulsiflability, up to and including a state of extremely hydrophile character, products are obtained of distinct and outstanding value for various uses and particularly for demulsification.

OXYALKYLATED BLOWN CASHEW NUTSHELL LIQUID Example 1 For convenience, the molecular weight of the oxidized or blown product is considered as the same as the original product; one pound mole of such blown cashew nutshell liquid (medium blown grade) is mixed with one-half of 1% of sodium methylate and subjected to reaction with two pound moles of ethylene oxide at a temperature between and 175 C. and a pressure between 125 pounds per square inch to pounds per square inch. The time required for such reaction is approximately 3-6 hours. The color was thinner, and more of a pale amber than in the case of the initial product prior to oxyalkylation,

and exhibits little or no hydrophile properties in dilute aqueous solution.

OXYALKYLATED BLOWN CASHEW NUTSHELL LIQUID Example 2 The same' procedure is employed as in "Oxyalkylated blown cashew nutshell liquid, Example 1, except that four moles of ethylene oxide are employed instead of two moles, and the resultant shows some degree of water-solubility, having a milky appearance in a dilute aqueous solution.

OXYALKYLATED BLOWN CASI-IEW NUTSHELL LIQUID Example 3 OXYALKYLATED BLOWN CASHEW NUTSHELL LIQUID Example 4 The same procedure is employed as in Oxyalkylated blown cashew nutshell liquid, Example 1, except that eight moles of ethylene oxide are employed instead of two moles. The product was amber, in color, and entirely hydrophile, giving a clear dilute aqueous solution.

OXYALKYLATED BLOWN CASHEW NUTSHELL LIQUID Example 5 The same procedure is employed as in the four examples preceding, except that propylene oxide or methyl glycidol is employed instead of ethyli h. V

7 OxYArKYLA'rEn BLOWN I CASHEW "Norsmim." LIQUID Example 6 "The same procedure is employed as in the preceding examples, except that-instead of employing a'mediumblowncashew nutshell liqui one employs either alight blown or heavilyblown cashew nutshell liquid.

We again Wish to emphasize that-our invention, in its broadest aspects, contemplates (1st) Blown cashew nutshell liquid and oxyall'iylated blown cashew nutshell liquid;

(2nd) A method of "making both of these two compositions; and

(3rd) The use of both of said compositions in various arts, including particularly breaking of oil field emulsions; and use as break inducersin doctor treatment, etc.

We desire to emphasize that in the hereto appended claims reference to the product being drastically-oxidized'v meansbxidation .by means of a gaseous oxygen-containing medium, such as air, dry or moist, ozonaozonized air, oxygen, etc. ilhe alkylene oxide employed is one having not more than 4 carbon atoms, and we particularly prefer-to employ ethylene. oxide. Although our invention has a dual aspect,.we attach the greater and most important significance to the oxyalkylated derivatives, the method of manufacturing same,- and their uses. What is said hereinafter as to theutility-of these products, applies particularlyto the oxyalkylated derivatives.

- Conventional d'emulsifying agents employed in thetrea-tment of oil field emulsions are used as such, or after dilution with any suitable solvent, such as water; petroleum hydrocarbons, such as benzene, toluene, xylene, tar acid-oil, cresol, an-.

thracene oil, etc. Alcohols,'particular aliphatic alcohols, such as methyl alcohol, ethyl alcohol, denatured alcohol, propyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol, etc., may be employed asdil-uents. Miscellaneous solvents, such as pine oil, carbon tetrachloride, sulfur dioxide extract obtained in the refining of petroleum, etc., may be employed as diluen-ts. Similarly, the material crmaterials employed-as the demulsiiying agent of our herein-.described-process for resolving-petroleum emulsions, may be admixed With one or more of the solvents customarily used in connection with conventional'demulsifying agents. Moreover, said material or materials may be used alone or in admixture with other suitable well known classes of demulsifying agents. I

It is well known, that conventional demulsifying. agents may be used in a water-soluble form, or in an oil-solubleform, or in a form exhibiting both oiland water solubility. Sometimes they may be used in a form which exhibits relatively limited oil solubility. However, 1 to 20 000, or even 1 to 30,000, or 1 to 40,000, or 1 to 50,000 in desalting practice, such an apparent insolubility in oil and water is not significant, because said reagents undoubtedly have solubility within the concentration employed, This same fact is true in regard to the material or materials employed as the demulsiiying agent of our process.

We desire to point out that the superiority of the reagent or clemulsifying agent contemplated in our process is based upon its ability to treat certain emulsions more advantageously and at somewhat lower cost than is possible with other available-demulsifiers, or conventional mixtures thereof. wltwis believed that the particular demulsifying agent or treating agent herein described will find comparatively limited application, :sofar asuth'e'majority of oilfield emulsions are: concerned; but we have found that such a.- deinulsifying agent hascommercial value, as it will economically break or resolve oil field emulsions in a number of cases which cannot be treated-as easily'orvat so low a cost with the demulsifying agents heretofore available.

In practising our process for resolving petroleurn emulsions of the 'water-in-oil type, a treating agent or demulsifying agent of the kind above described is brought into contact with or caused to act upon the emulsion to be treated, in any of the various apparatusnow generally used to resoive or break petroleum emulsions with a chemica1 reagent, the above procedure being used either alone or in combination with other demulsifying procedure, such as the electrical dehydration process.

The demulsifier herein contemplated may be employed in connection with what is commonly known as down-the-hole procedure, i. e., bringing the demulsifier in contact with the fluids of the well at the bottom of the well, orat some point prior'to the emergence of said fluids. This particular type of application is decidedly feasible-:when the demulsifier is usedin connection with acidification of calcareous oil-bearing strata, especially if suspended in or dissolved in the acid employed for acidification.

.Asomewhat analogous use of the new chemical product or compound herein described, is in the removal of aresidual mudv sheath which remains after drilling a well by the rotary method. Sometimes the drilling-mud contains added calcium carbonate'or the like to render the mud susceptible to reaction with hydrochloric acid or the-like, and thus expedite its removal.

Onefpreferred and more narrow aspect of our invention insofar-as-it is concerned with demulsificationofpetroleum emulsions of the waterin-oil type, is concerned with the admixture of the-new demulsifier herein described with a-viscosityereducing solvent such as the various solvents enumerated, particularly aromatic solvent, alcohols, ether alcohols, etc., as previously specified. Theword solv.ent.is used in this sense to refer to the mixture if more than one solvent is employed,- and generally speaking, it is our preference to employ the demulsifier in a form representing 25% to' 85% demulsifier and 15% to 75% solvent,..largely, if not entirely, non-aqueous and so selected as to give a solution or mixture particularly adaptable for proportional pumps or other measuring devices.

Attention is directed to the following fact: The herein described new chemical materials or products contain hydroxyl groups. The hydroxyl groups may be present as a result of terminal groups obtained by oxyalkylation, or may be present as part of original phenolic radicals, or they may be present in both forms. Obviously, such hydroxyl groups may be reacted further, for instance, with a polycarboxy acid oranhydride such-as phthalic anhydride, maleic anhydride, etc., or with alpha-halogenated monocarboxy acids. having less than 8 carbon atoms such as chloroacetic acid. Such derivatives, in turn, may be considered as intermediates for further reaction. For instance, the maleic acid derivatives may be-reacted with sodium bisulfite to introduce sulfonic groups, orthe chloroacetic derivative may be reacted with a tertiary amine, such as dimethyldodecylamine to produce a quaternary compound.

.Itis understood thatwhen intended to be used as reactants, the upper ratio of oxyalklating agent may well be double that previously referred to when measured in terms of moles added per phenolic radical, or measured in percentage increase in weight, based on the original resin.

In light of the usual knowledge of resin manufacture and insofar that resinification of the kind herein employed to produce a starting material, invariably and inevitably produces a mixture of analogous or related compounds, it is obvious that the subsequent derivatives must likewise invariably and inevitably represent a mixture in contradistinction to a single compound.

As has been previously pointed out, the reaction products of the kind herein described have a resinto wax-like and fat-like character, and solubility in water may vary from incipient selfemulsifiability to a'stage where a product gives a clear solution or sol, even in the presence of a modest amount of water-insoluble solvent, such as to of xylene.

The new chemical products or compounds herein described form the subject-matter of our co-pending application Serial No. 1,483, filed January 9, 1948.

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

1. A process of breaking emulsions of the Water-in-oil type, characterized by subjecting the emulsion to the action of a demulsiiying agent comprising an oxyalkylated, drastically-oxidized treated cashew nutshell liquid.

2. A process of breaking emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifying. agent comprising an oxyalkylated, drastically-oxidizedtreated cashew nutshell liquid, characterized by the fact that said oxidation is conducted by means of a gaseous oxygen-containin medium.

3. A process of breaking emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifying agent comprising an oxyalkylated, drastically-oxidized treated cashew nutshell liquid, characterized by the fact that said oxidation is conducted by means of a gaseous oxygen-containing medium, and with the proviso that said oxidation is stopped short of the sub-rubbery stage.

4. A process of breaking emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifying agent comprising an oxyethylated, drastically-oxidized treated cashew nutshell liquid.

5. A process of breaking emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a dernulsifying agent comprising an oxyethylated, drastically-oxidized treated cashew nutshell liquid, characterized by the fact that said oxidation is conducted by means or" a gaseous oxygen-containing medium.

6. A process of breaking emulsions oi the water-in-oil type, characterized by subjecting the emulsions to the action of a demulsifying agent comprising an oxyethylated, drastically-oxidized treated cashew nutshell liquid, characterized by the fact that said oxidation is conducted by means of a gaseous oxygen-containing medium, and with the proviso that said oxidation is stopped short of the sub-rubbery stage.

7. A process of breaking emulsions of the water-in-oil type, characterized by subjecting the emulsions to the action of a demulsifying agent comprising an oxyethylated, drastically-oxidized treated cashew nutshell liquid; said oxyethylation bein suficient to impart hydrophile properties, at least sufiicient to give self-emulsifiability.

3. A process of breaking emulsions of the water-in-oil type, characterized by subjecting the emulsions to the action of a demulsifying agent comprising an oxyethylated, drastically-oxidized treated cashew nutshell liquid, characterized by the fact that said oxidation is conducted by means of a gaseous oxygen-containing medium; said oxyethylation being sufiicient to impart hydrophile properties, at least suiiicient to give selfemulsifiability.

9. A process of breaking emulsions of the water-in-oil type, characterized by subjecting the emulsions to the action of a demulsifying agent comprising an oxyethylated, drastically-oxidized treated cashew nutshell liquid, characterized by the fact that said oxidation is conducted by means of a gaseous oxygen-containing medium, and with the proviso that said oxidation is stopped short of the sub-rubbery stage; said oxyethylation being suflicient to impart hydrophile properties, at least sufiicient to give self-emulsifiability.

MELVIN DE GROOTE. OWEN H. PETTINGJLL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,075,018 Bruson et a1 Mar. 30, 1947 2,278,838 De Groote et al. Apr. 7, 1942 2,307,058 Moeller Jan. 5, 1943 2,317,726 Boedeker et a1 Apr. 27, 1943 2,327,996 Burnam Aug. 31, 1943 2,417,739 De Groote Mar. 18, 1947 

